The Congelliere et al U.S. Pat. No. 3,694,603, discloses a "Push-Push Switch With Improved Alternate Make and Break Latching Mechanism." The present invention is an improvement of the switch therein disclosed which is capable of being configured as a push-push switch, a momentary on or momentary off switch with only slight modifications to essentially the same components.
The Congelliere et al switch, one of whose inventors is the present applicant, has been found to have several disadvantages which are overcome by the switch of the present invention. The referred-to switch is a push-push type switch which alternately makes and breaks an electrical circuit. However, as those skilled in the art are aware, other switch functions are also desirable, such as momentary on and momentary off. While the prior art discloses structures which can be employed for these switching functions, it would be desirable if the referred-to switch were also capable of these functions. I have found, that by slight modification of the referred-to switch, it can be made to perform the momentary on, or momentary off functions, or the push-push function.
Another aspect of the referred-to switch which has proven to be troublesome is the connection between the switch blades or contacts (switch blades C as illustrated in the patent) and the conductors (such as conductor 42) which serve to connect the switch to the device being controlled. If this connection fails, and such failure has been noticed in use, the switching arrangement becomes inoperative and therefore requires service.
In the referred-to switch an electrical connection is made between a pair of normally non-contacting conductors, by a moveable contact under the influence of a manually operable plunger. A ratchet mechanism allows alternate operation of the plunger to maintain the contact in retracted or projected positions with the cooperation of a coil spring which urges the contact into its retracted position. The contact bridges the electrical conductors in its retracted position. For a push-push switch, this allows the possibility of inadvertent making of the connection if a plunger is inadvertently depressed. For some uses, for example, a battery operated flashlight, this can be a serious disadvantage if the plunger remains inadvertently depressed for a substantial period of time, for in this condition the battery may be inadvertently depleted.
Finally, the highly stressed flexible spring blade contacts employed in the switch are subject to stress failure under use.